In the processing of poultry carcasses following cleaning, eviscerating, etc., the foot portion is cut away and the ends of the legs at the posterior of the carcass are wire-trussed together to provide hock clamps above the end of the backbone structure. After the usual chilling, the thigh portion over the femur bone and the leg portion over the tibiotarsus bone become relatively rigid and the knee joint therebetween projects forwardly. The wing portions extend outwardly and slightly downwardly.
Attempts to treat or streamline process such irregularly-shaped bodies by machine and process steps have long presented a problem. Not only are the carcasses difficult to handle by reason of the irregular shapes and projections, but also during the chilling and storing operations the wing and leg portions become further misshapen. Added to this is the fact that the carcasses come in varying sizes, both in length and height and other body conformations, and it is important that in an injection process employing hollow needles, etc. such implements must miss the bone structure and accurately penetrate the muscle portion.
A very real problem is to find a way for positioning the bird carcass for the treatment so that it is firmly and accurately held irrespective of size or conformation, while at the same time mechanically positioning the needles or other treating elements with respect to a key point of the carcass portion engaged in the positioning step so that the needles miss the bone structure and find proper location in the muscle meat.
We have discovered that a removable elongated abutment or stop can be provided for engaging an anterior portion of the dressed carcass for clamping and centering the carcass for the treating operation when the carcass is pushed or pressed against the abutment. Further, we have discovered that side slide rails can be provided with cam sockets for gripping the knees of the bird to further fix it in position for treatment. By equipping the rails with needles, etc. and supporting them for tilting and play, the hunting action of the rail cam sockets against the rigid knees of the carcass aligns the needles so that they miss the bone and find the knee and thigh muscle meat. Moving the abutment away permits ejection of the processed bird and restores the apparatus for receiving another carcass.
In the process, a socket pusher engages not only the backbone and hock portion of the carcass but also the clamped leg-ends, and thus a substantial force can be applied through the bone structure to clamp the carcass against the centering abutment or post.
Forward of the breast bone (sternum) of the bird is a V-shaped recess and when this receives the depending generally-vertical locator post and the carcass is pressed forwardly against it from the rear, there is an accurate alignment of the bird carcass so that the injection needles will miss the keel bone and be properly located in the breast muscle meat. Thus, irrespective of the bird's length, height, or size, the above positioning step rapidly and accurately places the bird in proper position with respect to the needles or other treating parts.